Aircraft ECS Bleed Manifold Control for Balanced Engine Airflow
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Solution Overview
Problem
Aircraft environmental control systems face challenges in balancing bleed air flow from multiple engines to maintain equal power and thrust, leading to asymmetrical thrust and increased workload for flight crews, without relying on additional costly and unreliable mass flow sensors.
Innovation Solution
An aircraft environmental control system that utilizes a bleed manifold and electronic hardware controller to balance bleed air flow from multiple engines based on manifold pressure, employing a nested feedback control loop to adjust valve positions and regulate bleed manifold pressure, thereby maintaining equal air flow rates without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional mass flow sensors are installed to measure and balance bleed air flow from multiple engines, then the precision of air flow measurement is improved, but the device complexity and cost increase, and reliability decreases due to additional components
Solution Approach 1:
The patent extracts the air flow measurement function from dedicated mass flow sensors and relocates it to the existing manifold pressure sensor. By measuring pressure at the manifold and using it to infer air flow rates from multiple engines, the system eliminates the need for separate mass flow sensors on each engine branch, thereby reducing device complexity while maintaining measurement capability
Solution Approach 2:
The manifold pressure sensor serves multiple functions: it measures the pressure of mixed bleed air from multiple engines, enables calculation of individual engine air flow rates through control algorithm, and provides feedback for balancing the air distribution. This multi-functional use of a single sensor reduces the total component count while achieving the measurement precision needed for air flow balancing
2Measurement precision
If additional mass flow sensors are installed to measure and balance bleed air flow, then the measurement capability is improved, but the reliability of the system deteriorates due to more components that can fail
Solution Approach 1:
The patent removes the requirement for additional mass flow sensors by extracting the measurement function to the existing manifold pressure sensor. This reduction in component count directly improves system reliability by eliminating potential failure points associated with additional sensors and their associated electronics
Solution Approach 2:
The system uses the manifold pressure sensor's inherent measurements to self-determine the air flow rates from multiple engines through control algorithms. This self-service approach eliminates the need for external measurement devices, thereby improving reliability while maintaining the capability to measure and balance air flows accurately
3Temperature
If bleed air flow from multiple engines is not balanced, then the air conditioning performance may be maintained, but asymmetrical thrust occurs and engine wear increases
Solution Approach 1:
The patent implements a feedback control system where the manifold pressure sensor continuously monitors the pressure of mixed bleed air, the controller calculates individual engine air flow rates based on this pressure data, compares them to determine imbalance, and adjusts valve positions to correct the imbalance. This closed-loop feedback ensures balanced air distribution from multiple engines, preventing asymmetrical thrust and unequal engine wear while maintaining air conditioning performance
Solution Approach 2:
The system dynamically adjusts the air flow parameters from multiple engines by changing valve positions based on real-time manifold pressure measurements. By modifying the flow parameters (air flow rates) through valve control, the system achieves balanced distribution from multiple engines, eliminating harmful effects of imbalance such as asymmetrical thrust and differential engine wear
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures balanced air flow rates between engines, reducing wear and workload for pilots by maintaining equal engine power and thrust, while eliminating the need for additional sensors, resulting in a more reliable and cost-effective system.
Implementation Method 1
The ECS balances the first bleed air flow and the second bleed air flow output from the first engine and second engine, respectively, based on a bleed manifold pressure of the bleed manifold
Data Source
AI summary
An aircraft includes a first engine that generates first bleed air flow and a second engine that generates second bleed air flow. The aircraft further includes an aircraft environmental control system (ECS) with a bleed manifold to collect the first bleed air flow and the second bleed air flow, and one or more air cycle machines to perform air conditioning consuming bleed air flow from the bleed manifold. The ECS balances the first bleed air flow and the second bleed air flow output from the first engine and second engine, respectively, based on a bleed manifold pressure of the bleed manifold.